PROVIDENCE, R.I. — Legislation was introduced on Wednesday that calls for the legalization of marijuana and the establishment of a system to regulate it.

By W. Zachary Malinowski

PROVIDENCE, R.I. — Legislation was introduced on Wednesday that calls for the legalization of marijuana and the establishment of a system that would regulate and tax the drug like liquor sales.

The bill is sponsored by Sen. Josh Miller, D-Cranston, chairman of the Senate Health and Human Services Committee, and Edith H. Ajello, D-Providence, chairwoman of the House Judiciary Committee.

The legislation, if it becomes law, would bar anyone under the age of 21 from possessing marijuana. Those of age would be allowed to possess up to an ounce of marijuana and grow no more than two mature marijuana plants in “an enclosed, locked space.”

Ajello said that a maximum of 10 marijuana stores statewide would be allowed to sell the drug.

“Smoking in public would continue to be illegal,” as well as driving under the influence of marijuana or selling it to anyone under the age of 21, she said. “I do not encourage or promote marijuana use.”

This is the fourth consecutive year that legislation has been introduced to legalize and regulate marijuana. The move does not come as a surprise, as Rhode Island has the nation’s highest unemployment rate, 9.1 percent, and lawmakers are searching for more sources of income for the state.

Miller said the state “desperately needs new revenue sources,” while Ajello said taxes from marijuana sales could generate “tens of millions of dollars” for Rhode Island. The legislation calls for an excise tax of up to $50 per ounce on transferring marijuana from the grower to a retail store and a special 10-percent tax on retail sales of the drug.

Among the sign-carrying supporters on hand was Brett Smiley, a Democratic candidate for mayor of Providence.

Over the past few years, marijuana use has also grown more acceptable. Rhode Island is 1 of 20 states and the District of Columbia to allow the sale of medical marijuana. Another 10 states are considering establishing medical-marijuana programs.

Ajello said that 26 other members of the House are supporting the legislation.

Recreational use of marijuana is now legal in Colorado and Washington state, and polls show that a majority of Americans, 55 percent, favor legalization of the drug. Last year, Rhode Island became one of 16 states to decriminalize marijuana possession.

In January, President Obama minimized the dangers of marijuana.

“As has been well documented, I smoked pot as a kid and I view it as a bad habit and a vice, not very different from the cigarettes that I smoked as a young person up through a big chunk of my adult life,” he told David Remnick, editor of The New Yorker magazine. “I don’t think it is more dangerous than alcohol.”

Still, the president said, he would not want his two daughters smoking marijuana.

Last spring, the state’s first two medical marijuana dispensaries opened for business — Thomas C. Slater Compassion Center in Providence and Greenleaf Compassionate Care Center in Portsmouth.

Figures from the state Health Department show that there are 6,975 patients in the Rhode Island medical marijuana program and a steady growth of registered users at the two dispensaries. Slater now has 2,625 men and women eligible to buy marijuana, while Greenleaf has climbed to 693 patients. Only patients who are registered with the state and designate the dispensaries as their suppliers are allowed to buy the drug.

But so far, the dispensaries have not generated much revenue for Rhode Island. Figures from the state Division of Taxation show that net patient revenue produced $137,106 in taxes for the first seven months of the fiscal year that ended on Jan. 31.

Net patient revenue is the gross amount that a dispensary receives in cash.

The tax revenue should grow this year, as Summit Medical Compassion Center, the third and final dispensary permitted under Rhode Island law, is scheduled to open in Warwick this spring.